Over 60% of Singapore’s coral reefs have
been lost to decades of coastal urbanization and heavy sedimentation has
restricted coral development to the upper 5
m of the reef slope. High species diversity, predictable mass
spawning events and vigorous growth of larval recruits indicate that active
rehabilitation can help enhance reef resilience to urbanization and climate
change impacts. Rehabilitation techniques selected should address high
sedimentation, destabilized reef
substrate and reef community
structure change. Coral species dominance has shifted to favor those more
tolerant of reduced light. Initiating rehabilitation with these dominant
species can stabilize the reef substrate quickly. Coral nurseries with raised
mesh-net platforms prevent sediment smothering and improve survival of coral
fragments and juveniles. Juveniles have also naturally recruited and developed
on seawalls constructed in non-reef areas. Innovative design and engineering of
coastal defenses can facilitate coral growth as sea level rises. Floating reefs
and seawalls that incorporate terraced tidal pools can encourage continued
growth and development of coral communities. Two approaches considered
appropriate to rehabilitating coral communities exposed to impacts of urbanization
and climate change are: (1) increase of live coral cover and diversity of degraded reefs; (2) creation of reef communities in
non-reef areas.